The present invention concerns new organometallic compounds and polymerization catalysts comprising the organometallic compounds.
During the last 20 years a lot of research has been carried out in order to establish the relation structure-reactivity in single site olefin polymerization catalysis. As a result, several information concerning the influence of the catalyst structure on molecular weight, tacticity and comonomer insertion are available today.
One of the first methods used for achieving a better control of the catalyst properties is the use of a bridge which renders two cyclopentadienyl ligands stereorigid. In this way, it has been possible to obtain highly isotactic and highly syndiotactic propylene polymers.
EP 416 815 discloses monocyclopentadienyl catalysts wherein a cyclopentadienyl ligand and an amido ligand are connected through a covalent bridge. The resulting catalyst can incorporate very efficiently long chain alpha-olefins.
In the last decade, a lot of effort have been dedicated to the development of these complexes and to the study of the influence of the ligand structure on catalyst activity.
It has been surprisingly found that it is possible to prepare organometallic compounds wherein a transition metal is bonded to three ligands which are rigidly connected through structural bridges, wherein at least one ligand is of the cyclopentadienyl type or is isolobal to cyclopentadienyl and the remainder(s) are monovalent anionic ligands. These complexes are effective catalysts for olefin polymerization. By varying the type of ligands and the structure of the two (or three) covalent bridges it is possible to modify the characteristics of the resulting catalyst in terms of molecular weight, comonomer incorporation and tacticity of the obtained polymer.
The organometallic catalysts of the invention are represented by general formula (I): 
wherein:
M is a transition metal of groups 3, 4-10, lanthanide or actinide of the periodic table of the elements, preferably titanium, zirconium or hafnium;
each R is independently a structural bridge rigidly connecting two ligands L1, L2 and L3 and is constituted by 1 to 4 chain atoms selected from carbon, silicon, germanium, oxygen, boron; these atoms can be part of fused rings, aromatic rings, aliphatic rings or spiro rings; preferred examples of groups R are: CR12, SiR12, CR12xe2x80x94CR12, CR12xe2x80x94SiR12, SiR12xe2x80x94SiR12;
wherein each R1 is independently selected from hydrogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C3-C20 alkenyl, optionally comprising 1 to 5 heteroatoms such as Si, N, P, O, F, Cl, Br, preferably R1 is selected from C1-C6 linear or branched alkyls; most preferably is methyl, ethyl, isopropyl, tertbutyl;
m, n and o are 0 or 1, with the proviso that m+n+o is 2 or 3;
L1 is a ligand of the cyclopentadienyl type or is isolobal to cyclopentadienyl, preferably a cyclopentadienyl, indenyl or fluorenyl ring, cyclopenteno[b]tiophenyl cyclopenteno[b:bxe2x80x2]-dithiophenyl cyclopenteno[b]pyrrolyl, boratabenzene, phospholyl, dihydroindeno[b]indolyl, optionally substituted by one or more R1 groups; most preferably a cyclopentadienyl, indenyl or fluorenyl ring, optionally substituted by one or more R1 groups;
L2 is a ligand defined as L1, or a monovalent anionic ligand selected from the group consisting of N, P, B when m+n=2, from the group consisting of NR1, PR1, BR1, O and S when m+n=1;
L3 is a monovalent anionic ligand selected from the group consisting of N, P, B when n+o=2, from the group consisting of NR1, PR1, BR1, O and S when n+o=1;
each X is independently selected from the group consisting of hydrogen, halogen, NR22, R2 with R2 equal to C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C3-C20 alkenyl, optionally comprising 1 to 5 heteroatoms such as Si, N, P, O, F, Cl, Br.
q is a number whose value is: 0, 1, 2 or 3, depending on the valence of the metal M, so that q+3 is the valence of M;
D is a neutral Lewis base, preferably it is selected from the group consisting of linear or cyclic ethers, amines and phosphines; most preferably it is selected from the group consisting of diethyl ether, tetrahydrofurane, aniline, dimethylaniline, triphenylphosphine, n-butylamine;
p is a number whose value is: 0, 1, 2 or 3.
When m is 1, n is 0 and o is 1, the formula I becomes the following formula Ia: 
When m is 1, n is 1 and o is 0, the formula I becomes the following formula Ib: 
When m is 1, n is 1, o is 0 and L2 is a ligand defied as L1 the formula I becomes the following formula Ic 
When m, n and o are 1 the formula (I) becomes the following formula Id 
It has been calculated using molecular modeling methods that compounds according to general formula (I) having three ligands rigidly interconnected can have a geometry wherein the bond angles of the metal M are more constrained than the catalyst disclosed in EP 416815. By varying the type of R and the ligands L1, L2 and L3 it is possible to vary the bond angle as well as the steric hindrance on the metal center, influencing in this way Mw, MWD, long chain branching, short chain branching and, in case of C3-C20 alpha olefins, the tacticity of the polymer.
A preferred class of compounds belonging to formula Ia is defined by the following formula II: 
wherein Cp is a cyclopentadienyl or indenyl ring, optionally substituted by one or more R1 groups, M is selected from Ti, Zr and Hf
each R is independently selected from CR12, SiR12, CR12xe2x80x94CR12, CR12xe2x80x94SiR12, SiR12xe2x80x94SiR12, wherein R1 is hydrogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C3-C20 alkenyl, optionally comprising 1 to 5 heteroatoms such as Si, N, P, O, F, Cl, Br. Two groups R1 bonded to the same or to adjacent atoms can unite to form a ring.
L2 and L3 are independently selected from the group consisting of NR1, PR1, BR1, O and S;
X is independently selected from the group consisting of hydrogen, halogen, NR2, R2 with R2 equal to C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C3-C20 alkenyl, optionally comprising 1 to 5 heteroatoms such as Si, N, P, O, F, Cl, Br.
D is a neutral Lewis base; preferably it is selected from the group consisting of linear or cyclic ethers, amines and phosphines; most preferably it is selected from the group consisting of diethyl ether, tetrahydrofurane, aniline, dimethylaniline, triphenylphosphine, n-butylamine;
p is a number whose value is: 0, 1, 2 or 3.
In one embodiment of the invention, the compounds of formula I are preferably obtained by reacting a compound of formula MXq+3 wherein M is a transition metal of groups 3, 4-10, lanthanide or actinide of the periodic table of the elements, X is a monovalent anionic ligand, preferably selected from the group consisting of N(CH3)2, benzyl, and q is 0, 1, 2, 3 depending on the valence of M, with a compound of formula III 
wherein L1 is a group of the cyclopentadienyl type or is isolobal to cyclopentadienyl, preferably a cyclopentadienyl, indenyl or fluorenyl ring, cyclopenteno[b]tiophenyl cyclopenteno[b:bxe2x80x2]-dithiophenyl cyclopenteno[b]pyrrolyl, boratabenzene, phospholyl, dihydroindeno[b]indolyl, optionally substituted by one or more R1 groups; most preferably a cyclopentadienyl, indenyl or fluorenyl ring, optionally substituted by one or more R1 groups;
m, n and o are 0 or 1, with the proviso that m+n+o is 2 or 3.
L2 is a ligand of the cyclopentadienyl type or is isolobal to cyclopentadienyl, preferably a cyclopentadienyl, indenyl or fluorenyl ring, cyclopenteno[b]tiophenyl cyclopenteno[b:bxe2x80x2]-dithiophenyl cyclopenteno[b]pyrrolyl, boratabenzene, phospholyl, dihydroindeno[b]indolyl, optionally substituted by one or more R1 groups; most preferably a cyclopentadienyl, indenyl or fluorenyl ring, optionally substituted by one or more R1 groups; or it is selected from the group consisting of N, P, B when m+n=2, it is selected from the group consisting of NR1, PR1, BR1, O and S when m+n=1;
L3 is selected from the group consisting of N, P, B when n+o=2, it is selected from the group consisting of NR1, PR1, BR1, O and S when n+o=1;
each R is independently a structural bridge rigidly connecting L1, L2 and L3 and is constituted by 1 to 4 chain atoms selected from carbon, silicon, germanium, oxygen, boron; these atoms can be part of fused rings, aromatics rings or spiro rings;
R1 is hydrogein, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C3-C20 alkenyl, optionally comprising 1 to 5 heteroatoms such as Si, N, P, O, F, Cl, Br.
In order to have complete substitution of three ligands X with L1, L2 and L3 it is in some cases preferable to remove from the reaction medium the compound XH formed during reaction. Depending on the reaction conditions, also the intermediate IV can be formed. 
The intermediate IV is then further reacted with a compound of formula II with X equal to benzyl, to produce the compound of formula I.
Alternatively, it is possible to react one mole of compound III with three moles of a strong base such as butyllithium, NaH, KH, etc. The trianion is then treated with MXq+3, optionally complexed with a Lewis base D, to obtain the compound of formula I, with X equal to halogen, preferably Cl.
Another suitable process for the preparation of compounds of formula I is to treat the compound (III) with NR3 in the presence of MXq+3.
The organometallic compounds of the present invention are useful as catalyst components for polymerizing olefins, preferably alpha-olefins in combination with a co-catalyst. Illustrative but non-limiting examples of co-catalysts are: aluminoxanes (methylalumninoxane (MAO), modified methylaluminoxane (MMAO), etc.), combinations of alkylaluminiums (such as trimethylaluminium, triethylaluminium, tributylaluminium, etc.) and boron Lewis acids (such as trifluoroborane, tris-pentafluorophenylborane, tris[3,5-bis(trifluoromethyl)phenyl]borane, etc.), and compounds of formula J+Kxe2x88x92 wherein J+ is able to react irreversibly with a group X in formula I and Kxe2x88x92 is an anion which is able to stabilize the catalytic species which originates from the reaction of the two compounds and which is sufficiently labile to be able to be removed from an olefinic substrate (triphenylcarbenium tetrakis(pentafluorophenyl)borate, dimethylanilinium tetrakis(pentafluorophenyl)borate, HBF4, AgBF4, AgPF6, AgSbF6, silver tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, etc.).
The catalyst component of the present invention, i.e. organometallic compound complex of formula I, can be used either as homogeneous catalyst or heterogeneous. In the latter case, it is preferred to use a organometallic compound (I) wherein at least one L group (selected from L1, L2 and L3) and/or one R group contains a functional group capable or forming a covalent bond with the support. Suitable functional groups are: xe2x80x94Oxe2x80x94SiR23. xe2x80x94SiR2nX3xe2x88x92n, SiR2n(OR2)3xe2x88x92n, xe2x80x94OH. This type of compounds are disclosed in EP 839 836, EP 757 992, EP 293 815, EP 953 580, EP 953 381 and WO 99/52949. The preferred functional group is xe2x80x94Oxe2x80x94SiR23 and is preferably linked to the organometallic compound through a divalent radical comprising from 1 to 20 carbon atoms and from 0 to 5 chain atoms different from carbon and preferably selected from silicon, oxygen, sulfur, boron, phosphorus, nitrogen.
The divalent radical joins the group xe2x80x94Oxe2x80x94SiR23 either to the Cp ring or to one of the atoms of R or to the anionic ligand, as described in EP 839 836.
As supporting material, any type of inorganic oxides are used, for example inorganic oxides such as: silica, alumina, silica-alumina, aluminum phosphates and mixtures thereof, obtaining supported catalysts with contents in transition metals between 0.01 and 4% by weight, preferably between 0.1 and 1%. A particularly preferred support is silica calcined at a temperature between 600xc2x0 C. and 800xc2x0 C. and also MAO modified silica.
For the polymerization in solution, the cocatalyst is mixed with a solution of a organometallic compound of formula I and a supplementary quantity of it optionally is added to the solution; or the catalyst can directly be added to the polymerization medium, which contains the cocatalyst.
For the polymerization in suspension, the cocatalyst is previously mixed with the supported solid catalyst or it is added to the polymerization medium before the supported catalyst, or both operations are sequentially realized.
The most proper polymerization procedure can change according to the chosen type of polymerization process (solution, suspension, slurry or gas phase).
The process consists in putting in contact the monomer, or, in certain cases, the monomer and the comonomer, with a catalytic composition according to the present invention, that includes at least one organometallic compound of formulas I and/or II, at a proper temperature and pressure.
C2-C12 alpha-olefins, such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, styrene, divinylbenzene are used as monomer. In case ethylene is used as monomer, it can be either homopolymerized, or copolymerized in the presence of at least one comonomer selected from propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene. These comonomers are used in proportions from 0.1 to 70% by weight of the total of the monomers. In the case of homopolymerization of ethylene the density of polymers ranges between 0.950 and 0.970 kg/cm3 in the case of copolymerization of ethylene the density is as low as 0.880 kg/cm3.
In the particular case of the polymerization technique known as suspension or slurry process, the used temperature will be between 30xc2x0 and 110xc2x0 C., the same which is typically used in gas phase, while for the solution process the usual temperature will be between 120xc2x0 and 250xc2x0 C.
Preferred compounds of formula I are: 
Further examples of compounds belonging to the invention are obtained by substituting zirconium in the above listed compounds with titanium or hafnium.
These compounds can be synthesized starting from the corresponding compound of formula III, which can be synthesized using methods similar to those described in the experimental part starting from the appropriate cyclopentadienyl derivative, Me2SiCl2 and amine derivatives. 
Further examples include compounds wherein the tetrahydrofairane ligand in the previous examples shown in b) is replaced by pyrydine.
These compounds can be synthesized starting from the corresponding compound of formula III, which can be synthesized using methods similar to those described in the experimental part starting from the appropriate cyclopentadienyl derivative, Me2SiCl2 and amine derivatives. The corresponding compound of formula I can be synthesized using similar methods to those described in the experimental part starting from the compound of formula III and the appropriate chromium III complex, such as CrCl3(THF)2.
c) 
Further examples include compounds wherein the zirconium atom in the previous examples shown in c) is replaced by Ti, Hf
These compounds can be synthesized starting from the corresponding compound of formula III, which can be synthesized using methods similar to those described in Organometallics 1997, 16, 2891; Topics in Catalysis 7, 1999, 37; Eur. J. Inor. Chem. 1998, 1153.
d) 
Further examples include compounds wherein the zirconium atom in the previous examples shown in d) is replaced by Ti, Hf
These compounds can be synthesized starting from the corresponding compound of formula III, which can be synthesized using methods similar to those described in Organometallics 19,2000, 4071.
e) 
Further examples include compounds wherein the zirconium atom in the previous examples shown in e) is replaced by Ti, Hf
These compounds can be synthesized starting from the corresponding compound of formula III, which can be synthesized using methods similar to those described in EP0839834, EP416185.
f) 
Further examples include compounds wherein the zirconium atom in the previous examples shown in f) is replaced by Ti, Hf
The previous compounds can be synthesized using similar methods described in the literature. The corresponding compound of formula III can be synthesized using similar methods to those described in J. Organomet. Chem. 558, 1998, 139; Chem. Ber. 1996, 129, 275 starting from the appropriate cycolpentadienyl derivative and the appropriate protected amine or alcohol followed by deprotection.
g) 
Further examples include compounds wherein the zirconium atom in the previous examples shown in g) is replaced by Ti, Hf.
These compounds can be synthesized starting from the corresponding compound of formula III, which can be synthesized using methods similar to those described in EP953581, EP839836 and European patent application number 99500196.3.
h) 
Further examples include compounds wherein the zirconium atom in the previous examples shown in h) is replaced by Ti, Hf.
These compounds can be synthesized starting from the corresponding compound of formula III, which can be synthesized using methods similar to those described in Organometallics 1999, 18, 4147.
Synthesis of Compounds 1-9
All manipulations were performed under an inert atmosphere of argon or nitrogen using syringes or cannulae through Subaseals in Schlenk tubes using high vacuum line techniques or a glovebox. Solvents were dried and distilled under nitrogen: diethyl ether and tetrahydrofurane from sodium benzophenone ketyl; benzene and toluene from sodium and hexane from sodium/potassium alloy. Compound C5H4-1,1-(SiMe2Cl)2 was prepared according to Organometallics, 1985, 4, 2206. The 1H and 13C NMR spectra were recorded at 299.95 and 75.43 MHz respectively on a Varian Unity 300 spectrometer; chemical shifts, in ppm, are positive downfield with respect external SiMe4; coupling constants are in Hz. IR spectra were recorded in Nujol mulls for solids on a Perkin-Elmer 583 spectrophotometer. C and H analyses were performed with a Perkin-Elmer 240-B microanalyzer.
Preparation of C5H4[SiMe2(NHtBU)]2 (1)
A solution of 2.1 equivalents of LiNHtBu in THF was added at 0xc2x0 C. to a solution of 1 equivalent of C5H4-1,1-(SiMe2Cl)2 in THF and the mixture was stirred for 12 h. The volatiles were removed under vacuum and the residue extracted with hexane to give (1) as a yellow oil in 90% yield.
Preparation of [Zr{xcex75-C5H3[SiMe2(NHBut)][SiMe2(xcex71-NBut)}(NMe2)2] (2)
A solution of Zr(NMe2)4 (3.37 g, 12.6 mmol) in THF (70 mL) was cooled to 0xc2x0 C. and 1 (4.09 g, 12.6 mmol) was added by syringe. The resulting yellow solution was refluxed during 5 h. When the gas stopped the solvent was removed under vacuum and the residue was extracted into pentane (70 mL). After filtration and removal of the solvent complex 2 was isolated as a light brown oil. (6.19 g, 12.3 mmol, 98%). 1H-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex40.35 (s, 3H, SiMe2NHtBu), 0.42 (s, 3H, SiMe2NHtBu), 0.57 (s, 3H, SiMe2NtBu), 0.59 (s, 3H, SiMe2NtBu), 0.85 (s, 1H, NHtBu), 1.11 (s, 9H, NHtBu), 1.27 (s, 9H, NtBu), 2.81 (s, 6H, NMe2), 2.82 (s, 6H, NMe2), 6.39 (m, 1H, C5H3), 6.47 (m, 1H, C5H3), 6.69 (m, 1H, C5H3); 13C-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex42.3 (SiMe2), 2.7 (SiMe2), 2.8 (SiMe2), 3.0 (SiMe2), 33.9 (NHtBu), 34.9 (NtBu), 44.2 (NMe2), 44.5 (NMe2), 49.6 (NHtBuipso), 56.6 (NtBuipso), 111.4 (C5H3ipso), 122.6 (C5H3), 122.9 (C5H3); 124.6 (C5H3), 126.7 (C5H3). IR (Nujol) xcexd=3384 cmxe2x88x921 (Nxe2x80x94H). Anal. Found: C, 49.73; H, 9.05; N, 11.45. Calc.: C, 50.24; H, 9.24; N, 11.16.
Preparation of [Zr{xcex75-C5H3-1,3-[SiMe2(xcex71-NBut)]2}(NMe2)] (3)
When a 1/1 molar ratio of [Zr{xcex75-C5H3-1,3-[SiMe2(xcex71-NBut)]2}(CH2Ph)] (see preparation (5) below) and the diamido 2 derivatives in C6D6 was heated for 12 h to 120xc2x0 C. in a sealed NMR tube, the amido compound 3 was formed as the unique reaction product and identified by NMR spectroscopy. 1H-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex40.51 (s, 6H, SiMe2), 0.55 (s, 6H, SiMe2), 1.31 (s, 18H, NtBu), 2.77 (s, 6H, NMe2), 6.34 (m, 1H, C5H3), 6.78 (m, 2H, C5H3); 13C-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex42.9 (SiMe2), 3.0 (SiMe2), 35.6 (NtBu), 45.1 (NMe2), 55.8 (NtBuipso), 117.7 (C5H3ipso) 119.8 (C5H3), 133.2 (C5H3).
Preparation of [Zr{xcex75-C5H3[SiMe2(NHBut)][SiMe2(xcex7t-NBut)}(CH2Ph)2] (4)
A solution of Zr(CH2Ph)4 (2.93 g, 6.43 mmol) in toluene (70 ml) was cooled to 0xc2x0 C. and 1 (2.09 g, 6.43 mmol) was added by syringe. The resulting yellow solution was warmed to 45xc2x0 C. for 5 h. The solvent was removed under vacuum and the residue was extracted into pentane (70 ml). After filtration and removal of the solvent a mixture of complexes 4 and 5 was isolated. Formation of 4 was confirmed by IR and NMR spectroscopy although pure 4 free of 5 could not be isolated. IR (Nujol): xcexd=3353 cmxe2x88x921 (Nxe2x80x94H). 1H-NMR (300 MHz, C6D6, 20xc2x0 C., TMS) for 4: xcex40.33 (s, 3H, SiMe2), 0.34 (s, 3H, SiMe2), 0.35 (s, 3H, SiMe2), 0.40 (s, 3H, SiMe2), 0.69 (s, 1H, NHtBu), 1.06 (s, 9H, NHtBu), 1.13 (s, 9H, NtBu), 1.66 (s, 1H, CH2Ph), 1.72 (s, 1H, CH2Ph), 2.12 (s, 1H, CH2Ph), 2.17 (s, 1H, CH2Ph), 6.21 (m, 1H, C5H3), 6.35 (m, 1H, C5H3), 6.60 (m, 1H, C5H3), 6.90-7.30 (m, 10H, C6H5). 13C-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex41.3 (SiMe2), 2.4 (SiMe2), 2.5 (SiMe2), 2.8 (SiMe2), 33.7 (NHtBu), 33.8 (NtBu), 49.7 (NHtBuipso), 54.9 (CH2Ph), 57.1 (NtBuipso), 57.9 (CH2Ph), 109.6 (C5H3ipso), 122.2 (C5H3), 122.5 (C5H3), 124.2 (C5H3), 125.6 (C5H3), 125.9 (C6H5), 126.4 (C6H5), 126.6 (C6H5), 127.8 (C6H5), 129.3 (C6H5), 129.6 (C6H5), 129.6 (C6H5), 129.8 (C6H5), 131.9 (C6H5), 145.8 (C6H5ipso), 146.2 (C6H5ipso).
Preparation of [Zr{xcex75-C5H3-1,3-[SiMe2(xcex71-NBut)]2}(CH2Ph)] (5)
A solution of Zr(CH2Ph)4 (2.93 gr, 6.43 mmol) in toluene (70 ml) was cooled to 0xc2x0 C. and 1 (2.09 g, 6.43 mmol) was added by syringe. The resulting yellow solution was refluxed for 5 h. The solvent was removed under vacuum and the residue was extracted into pentane (70 ml). After filtration and removal of the solvent complex 5 was isolated as a brown oil. (3.20 g, 6.34 mmol, 99%). 1H-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex40.40 (s, 6H, SiMe2), 0.42 (s, 6H, SiMe2), 1.27 (s, 18H, NtBu), 2.12 (s, 2H, CH2Ph), 6.14 (m, 1H, C5H3), 6.53 (m, 2H, C5H3) 6.9-7.23 (m, 5H, C6H5). 13C-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex42.4 (SiMe2), xcex42.4 (SiMe2), 35.8 (NtBu), 55.7 (CH2Ph), 57.1 (NtBuipso), 116.5 (C5H3ipso), 120.7 (C5H3), 126.4 (C5H3), 128.5 (C6H5), 129.8 (C6H5), 132.7 (C6H5), 150.6 (C6H5ipso). Anal. Found: C 57.01; H, 7.65; N, 5.48. Calc.:C, 57.20; H, 8.00; N, 5.56.
Preparation of [Ti{xcex75-C5H3[SiMe2(NHBut)][SiMe2(xcex71-NBut)}(CH2Ph)2] (6)
A solution of Ti(CH2Ph)4 (2.14 g, 5.2 mmol) in toluene (70 ml) was cooled to 0xc2x0 C. and 1 (1.69 g, 5.2 mmol) was added by syringe. The resulting yellow solution was warmed to 65xc2x0 C. for 5 h. When evolution of gas stopped the solvent was removed under vacuum and the residue was extracted into pentane (70 ml). After filtration and removal of the solvent complex 6 was isolated as a red solid. (2.87 g, 5.2 mmol, 100%). 1H-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex40.21 (s, 3H, SiMe2), 0.27 (s, 3H, SiMe2), 0.37 (s, 3H, SiMe2), 0.38 (s, 3H, SiMe2), 0.72 (s, 1H, NHtBu), 1.07 (s, 9H, NHtBu), 1.44 (s, 9H, NtBu), 2.47 (d, 2H, J=10.5 Hz, CH2Ph), 2.55 (d, 2H, J=10.5 Hz, CH2Ph), 2.81 (d, 2H, J=10.5 Hz, CH2Ph), 2.97 (d, 2H, J=10.5 Hz, CH2Ph), 5.83 (m, 1H, C5H3), 6.14 (m, 1H, C5H3), 6.83 (m, 1H, C5H3), 6.87-7.20 (m, 10H, CH2Ph); 13C-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex40.6 (SiMe2), 1.5 (SiMe2), 2.4 (SiMe2), 2.9 (SiMe2), 33.8 (NHtBu), 34.3 (NtBu), 49.8 (NHtBuipso), 61.5 (NtBuipso), 79.6 (CH2Ph), 83.7 (CH2Ph), 110.2 (C5H3ipso), 122.1 (C5H3), 122.5 (C5H3), 123.0 (C5H3), 125.9 (C5H3), 126.8 (C6H5), 126.8 (C6H5), 127.4 (C6H5), 128.5 (C6H5), 128.6 (C6H5), 128.7 (C6H5), 128.9 (C6H5), 129.8 (C6H5), 132.6 (C6H5), 149.6 (C6H5ipso), 150.1 (C6H5ipso). IR(nujol); xcexd=3349 cmxe2x88x921(Nxe2x80x94H). Anal. Found: C, 62.58; H, 8.75; N, 6.08; Calc.: C, 62.68; H, 8.68; N, 5.76.
Preparation of [Ti{xcex75-C5H3-1,3-[SiMe2(xcex71-NBut)]2}(CH2Ph)] (7)
A solution of Ti(CH2Ph)4 (5.34 g, 12.9 mmol) in toluene (70 ml) was cooled to 0xc2x0 C. and 1 (4.21 g, 12.9 mmol) was added by syringe. The resulting deep red solution was refluxed for 5 h. The solvent was removed under vacuum and the residue was extracted into pentane (70 ml). After filtration and removal of the solvent complex 7 was isolated as a deep red solid. (5.93 g, 12.9 mmol, 100%). 1H-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex40.39 (s, 6H, SiMe2), 0.40 (s, 6H, SiMe2), 1.42 (s, 18H, NtBu), 2.61 (s, 2H, CH2Ph), 6.14 (m, 2H, C5H3), 6.40 (m, 1H, C5H3), 6.89 (m, 1H, C6H5), 7.00 (m, 2H, C6H5), 7.22 (m, 2H, C6H5); 13C-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex42.1 (SiMe2), 2.2 (SiMe2), 35.6 (NtBu), 59.3 (NtBuipso), 69.6 (CH2Ph), 117.7 (C5H3ipso), 121.5 (C5H3), 126.3 (C5H3), 128.5 (C6H5), 130.3 (C6H5), 132.6 (C6H5), 152.4 (C6H5ipso). Anal. Found: C, 67.36; H, 8.75; N, 5.07. Calc.: C, 67.82; H, 8.71; N, 4.81.
Preparation of [Zr{xcex75-C5H3-1,3-[SiMe2(xcex71-NBut)]2}]+[(CH2Ph)B(C6F5)3]xe2x88x92 (8)
A toluene (20 m) solution of the monobenzyl complex 5 (0.116 g, 0.25 mmol) was treated with B(C6F5)3 (0.126 g, 0.25 mmol) at room temperature and the mixture was stirred for 30 m and cooled to xe2x88x9235xc2x0 C. The solvent was filtered off from the resulting insoluble residue which was then dried under vacuum to give 8 (0.21 g, 83% yield) as a dark brown oil. 1H-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex40.17 (s, 6H, SiMe2), 0.36 (s, 6H, SiMe2), 0.99 (s, 18H, NtBu), 3.42 (s, 2H, BCH2), 5.20 (m, 1H, C5H3), 6.01 (m, 2H, C5H3), 6.10 (m, 1H, p-C6H5), 6.34 (m, 2H, m-C6H5), 6.87 (m, 2H, o-C6H5). 13C-NMR (300 MHz, C6D6, 20xc2x0 C. TMS): xcex41.5 (SiMe2), 1.6 (SiMe2), 34.8(NtBu), 58.6 (NtBuipso), 121.4 (C5H3ipso) 127.4 (C5H3), 127.5 (C5H3), 127.9 (C6H5), 128.1 (C6H5), 128.3 (C6H5), 136.5 (C6F5), 138.3 (C6F5), 147.8 (C6F5), 149.8 (C6F5), 162.0 (C6H5ipso) 19F-NMR (300 MHz, C6D6, 20xc2x0 C., CCl3F); 132.1 (m, 2F, o-C6F5), 163.6 (m, 1F, p-C6F5), 167.2 (m, 2F, m-C6F5).
Preparation of [Ti{xcex75-C5H3-1,3-[SiMe2(xcex71-NBut)]2}]+[(CH2Ph)B(C6F5)3]xe2x88x92 (9)
A toluene (20 ml) solution of the monobenzyl complex 7 (0.125 g, 0.25 mmol) was treated with B(C6F5)3 (0.126 g, 0.25 mmol) at room temperature and the mixture was stirred for 30 m and cooled to xe2x88x9235xc2x0 C. The solvent was filtered off from the resulting insoluble residue which was then dried under vacuum to give 9 (0.13 g, 60% yield) as an orange crystalline solid. 1H-NMR (300 MHz, C6D6, 20xc2x0 C., TMS): xcex40.19 (s, 6H, SiMe2), 0.38 (s, 6H, SiMe2), 1.12 (s, 18H, NtBu), 3.49 (s, 2H, BCH2), 5.03 (m, 1H, C5H3), 5.86 (m, 2H, C5H3), 6.21-7.10 (m, 5H, C6H5). Compound 9 was only slightly soluble in C6D6, and its 13C NMR spectrum could not be recorded. 19F-NMR (300 MHz, C6D6, 20xc2x0 C., CCl3F): 132.1 (m, 2F, o-C6F5), 163.6 (m, 1F, p-C6F5), 167.2 (m, 2F, m-C6F5).
Polymerization of Ethylene